Automatic characteristic control and indication means



United States Patent 3,533,909 AUTOMATIC CHARACTERISTIC CONTROL AND INDICATION MEANS William N. Bennett, South Miami, Fla., assignor to Litton Business Systems, Inc., Fitchburg, Mass., a corporation of New York Filed Apr. 17, 1967, Ser. No. 631,379

Int. Cl. D21 US. Cl. 162-253 7 Claims ABSTRACT OF THE DISCLOSURE This invention provides for the correction of variations in the moisture content of a traveling paper web during production. Sensing stations are provided at selected machine positions to sense the moisture content of the Web. If the web is too wet corrective actions such as a decrease in the water added to the pulp, a decrease in machine speed, or an increase in drying is affected. A too dry web will have the reverse affect. In either case the web is marked to permit removal of the unusable portions. Provision is also made to initial correction when the web is in a marginal condition approaching either extreme. The controls are facilitated by the novel use of a standard moisture profile indicator.

BACKGROUND OF THE INVENTION Field of the invention The invention provides for the control of web characteristics under various conditions of web production and processing and is useful in paper making and treating, textile making and treating, and similar fields. Although the description of the preferred embodiment deals with moisture control in the paper making process, the invention is applicable to most web making and treatment processes.

Description of the prior art Prior art devices did not provide for automatic control of web processing but required human intervention. An operator would watch instruments such as the moisture profile indicator and employing his best judgment would initiate corrective action. No provision existed to mark rejected portions having undesirable characteristics.

SUMMARY OF THE INVENTION This invention relates to means for automatically adjusting various characteristics of the processing of a traveling web, as for instance, drying paper in paper making automatically by the use of sensors which instantly permit the determination of the percentage of moisture at any selected segment of the web as it passes a predetermined location. Ordinarily the sensor of a moisture profile indicating instrument will be located near the reel but sensors can also be located at other points along the length of the web processing machine such as after the application of moisture, coating materials, etc., in order to permit the determination of whether the web is too wet or too dry.

It is an object of this invention to control the moisture content of a traveling web to produce a uniform moisture profile by the use of substantially instantaneous signals to other parts of the web processing machine, actuating mechanisms to correct a too wet or a too dry condition. This is done in combination with time delay apparatus to prevent over-correction of the mechanism in the event of a deleterious spot condition. If the condition should persist for a predetermined length of time, for example, four seconds, as can be set on a time interval switch, then and then only will a signal be passed to the mechanism Patented Oct. 13, 1970 of the machine to correct the particular inequality encountered.

Also, the same apparatus can be utilized for indicating marginal conditions which are acceptable but are approaching unacceptable conditions, and these can be corrected before they become unacceptable conditions, or where the condition has become unacceptable, as where the web is too wet or too dry the mechanism is used to indicate directly on the web that it is to be rejected as long as the particular condition lasts.

Certain elements which can be adjusted by the system disclosed in this invention relate to adding or subtracting Water from the pulp, increasing or decreasing the web speed, or altering the drying effect of the related drying apparatus. In these and other ways, adjustments are provided to automatically and accurately control the moisture profile of the traveling web and thereby increase the yield of paper making machinery over that produced by machinery disclosed in the prior art.

Other objects and advantages of the invention will appear hereinafter.

Reference is to be had to the drawing which illustrates the invention in diagrammatic form.

In the drawing, the reference character 10 indicates a movable member such as for instance a needle in a conventional moisture indicating device coupled to a sensor 11 placed adjacent the traveling web. Needle 10 will move to the left to indicate that a particular segment of the web being sensed is becoming too wet or that it has become too Wet, or will move to the right to indicate that the web, at the point being sensed, is getting dry or has become too dry. This needle 10, in so indicating, can be utilized to sweep over and contact a series of contacts 12, 14, 16, 18, and 20. In the drawing, the needle 10 is shown contacting the central point of the contact 14, segment 14 labeled getting wet. At this moisture level the paper will be acceptable, but if the needle should pass into the contact 12, then the paper is too wet and has to be rejected. Similar conditions in the dry range apply to the contacts 18 and 20. The central contact 16 shows that the particular point under observation by the instrument has just about the right moisture content desired.

Contact 12, the wet indicating contact, is coupled via line 40, diode 42, to the stepping coil 44 of adjustable time interval or delay switch 22. The stepping coil 44 controls the stepping contact 30 for movement from its preset position to the zero position in discrete steps. As shown, the switch 22 has six contact positions to which the stepping contact 30 may be set to establish the time delay before signals are issued by switch 22 to begin corrective action such as reduce the water content of the pulp, decrease the paper making machine speed, or increase dryer action. The steps of the switch 22 may be one second intervals or any other convenient time period. When operated by stepping coil 44, the stepping contact will step to zero and complete the circuit path to provide the required control signals on line 23. The contact 12 is also coupled via diode 46, and line 48, to the stepping coil 50 and the stepping contact of adjustable time interval or delay switch 26. Switch 26 will step from its preset value (0 to 6 as with switch 22) to zero and issue a mark reel edge signal on line 54 to mark the paper web to indicate the start of an area too wet or too dry to use. Contact 14 is coupled via line 56 and diode 58 to the stepping coil 44 and stepping contact 30 to permit correction to begin as the web approaches the marginal wet condition.

The dry contact 20 is coupled via line 60 and diode 62 to the steping coil 64 and stepping contact 66 of adjustable time interval or delay switch 24. Switch 24 will step from a preset value (0 to 6) to zero and initiate control signals on line 68 to add water to the pulp, speed up the paper making machine, decrease drying or otherwise correct for the excessive Web dryness. The dry contact 20 is also coupled via diode 70 to the line 48 to cause reject marking of the web in the manner described above with reference to wet contact 12. Contact 18 is coupled by line 72 and diode 74 to the stepping coil 64 and stepping contact 66 of switch 24. This permits the commencement of the correcting action when a marginal dry condition exists.

The contact 16 is coupled via line 76 to a reset solenoid 28 which is mechanically coupled to the stepping contacts 30, 52, and 66 to reset them to an off zero position so that further control signals are terminated. Thus when the web moisture returns to the desired level all correction controls are removed. Additionally, contact 16 is coupled by line 78 to an And gate 80. And gate 80 receives a mark signal on line 54 and the reset signal on line 78, and produces the end mark signal to show that the following portion of the web is acceptable and that the unacceptable portion is ended. The mark and end mark signals facilitate the removal of the rejection portion of the web. These marks can of course, be a line printed on the paper, or perforations made by a wheel, etc., or any other well-known device can be used for this purpose.

The moisture profile detector instrument is a well-known commercial device as are the time interval switches but the combination of these switches, with the moisture pro- :file detector and the adjustments and reject indications utilized are believed to be novel and it is to this particular combination that the invenion is directed.

Having thus described my invention and the advantages thereof, I do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:

1. An automatic characteristic control apparatus for controlling the characteristics of material being processed comprising:

(a) sensing means disposed to coact with material when being processed upon relative movement between said material and said sensing means and, so as to sense a predetermined characteristic of said material;

(b) output means coupled to said sensing means and responsive to the operation thereof to assume one of a plurality of conditions indicative of the characteristic being sensed;

(c) characteristic control means coupled to said output means so as to be operated in discrete ways to provide an appropriate control depending upon the condition assumed by said output means; and

(d) material indication means coupled to said output means and responsive to only predetermined ones of said conditions to place upon the material being processed an indication of said predetermined ones of said conditions.

2. An automatic characteristic control apparatus as defined in claim 1, wherein adjustable time delay means are coupled between said output means and said characteristic control means to prevent said characteristic control means from operating for a predetermined period of time whereby the characteristic being sensed must persist longer than said predetermined period of time for said characteristic control means to operate.

3. An automatic characteristic control apparatus as defined in claim 2, further comprising a material handling apparatus for moving said material with respect to said sensing means.

4. An automatic characteristic control apparatus as defined in claim 3, wherein said material is a continuous web and the characteristic to be controlled is moisture.

5. An automatic characteristic control apparatus as defined in claim 4, wherein said output means is a moisture profile indicator having a dial with a plurality of conductive segments, each arranged to indicate a discrete moisture condition, said indicator further having an indicating movement responsive to the moisture sensed by said sensing means from said web for positioning a selector with respect to one of said conductive segments to provide an operative path between said indicating means segment and said characteristic control means.

6. An automatic characteristic control apparatus as defined in claim 5, wherein said control means comprises moisture control means for controlling the moisture added to the web and drying means for controlling the amount of drying applied to said web.

7. An automatic characteristic control apparatus as defined in claim 6, wherein said characteristic control means comprises first control means coupled to said moisture control means to add or subtract moisture from said web; second control means coupled to said material handling aparatus to speed up or slow down the moving of said web, and third control means coupled to said drying means to increase or decrease drying of said web, said first, second, and third control means being responsive to disposition of said selector on a predetermined use of said conductive segments to cause the operation of their associated means.

Kasser: Initial Operation of a Board Mill Automation System from Pulp & Paper Magazine of Canada, pp. T379T387, July 1965.

HOWARD R. CAINE, Primary Examiner US. Cl. X.R. 

